INFLAMMATORY CYTOKINE EXPRESSION IN HUMAN LUNG EPITHELIAL CELLS DURING PARACOCCIDIOIDES BRASILIENSIS INFECTION

Paloma Korehisa Maza (UNIFESP); Marcos Sergio Toledo (UNIFESP); Helio Kiyoshi Takahashi (UNIFESP); Anita Hilda Straus (UNIFESP); Erika Suzuki (UNIFESP)

Airway epithelial cells play an important role in maintenance of mucosal integrity and represent the first line of defense against pathogenic microorganisms which invade the lungs. In addition, epithelial cells contribute to pulmonary mucosal immunity by producing inflammatory mediators, such as cytokines. Paracoccidioides brasiliensis is a dimorphic fungus that causes a systemic mycosis in humans, whose infection occurs by inhaling mycelial forms of this fungus, with subsequent conversion to yeast forms and establishment of infection in host lungs. In this study we demonstrate the ability of P. brasiliensis to induce mRNA expression of inflammatory cytokines in human lung epithelial cells A549. Cells were incubated with formaldehyde-fixed (FY) or live (LY) yeast forms of P. brasiliensis for different periods of time (16-96 h). Reverse Transcription-Polymerase Chain Reaction was performed using specific primers for human IL-6, IL-1b, TNF-a and IL-8, and products were separated on agarose gel. For IL-1b, it was observed a slight increase of mRNA levels in A549 cells incubated with FY P. brasiliensis at 24 h, which was sustained up to 96 h. On the other hand, for both FY- and LY-incubated A549 cells, it was verified that IL-6, IL-8 and TNF-a mRNA expression were greatly increased when compared to basal levels. Interestingly, peaks for all cytokines studied were observed 24 hours earlier for FY than LY P. brasiliensis- incubated A549 cells (peak was reached at 24 h for FY and at 48 h for LY). Taking together, these results indicate that P. brasiliensis is able to induce expression of inflammatory cytokines in A549 cells, suggesting that pulmonary epithelial cells may participate in early host immune response in this fungal infection. Cell signaling pathways involved in this process are under investigation in our laboratory.